Rice Science最新文献

Convenience rice has become widely popular due to its easy availability for cooking. This study investigated the starch structure and composition of leachate and the microstructure of reheated convenience rice using novel processing technologies: super-heated steaming (SHS), auto-electric cooking (AEC), and pressurized-steam cooking (PSC). Additionally, the effect of two different target water contents (58% and 63%) was also evaluated. The PSC_63% sample had the highest total solids and amylopectin amount in the leachate. The amylopectin amount in the leachate differed significantly based on the targeted water content. Morphological characterization revealed that the swelling of starch and the coated layer on the surface of rice grains were most pronounced in the PSC_63% sample due to the pressure processing. The textural hardness of the AEC_58% sample was much higher than that of the other samples. The PSC_63% sample had the highest textural adhesiveness value, which can be attributed to the highest amylopectin amount in the leachate. Sensory characterization showed that the PSC_63% sample had the highest glossiness, whiteness, moistness, and overall acceptability. The principal component analysis score plots presented substantial differences in the leachate and textural and sensory characteristics of reheated convenience rice among the different processing technologies.

Phosphorus (P) levels alter the allelopathic activity of rice seedlings against lettuce seeds. In this study, we investigated the effect of P deficiency on the allelopathic potential of non-pigmented and pigmented rice varieties. Rice seedlings of the white variety Khao Dawk Mali (KDML105, non-pigmented) and the black varieties Jao Hom Nin (JHN, pigmented) and Riceberry (RB, pigmented) were cultivated under high P (HP) and low P (LP) conditions. Morphological and metabolic responses to P deficiency were investigated. P deficiency inhibited shoot growth but promoted root growth of rice seedlings in all three varieties. Moreover, P deficiency led to decreased cytosolic phosphate (Pi) and total P concentrations in both shoot and root tissues. The subsequent reduction in internal P concentration enhanced the accumulation of phenolic compounds in both shoot and root tissues of the seedlings. Subsequently, allelopathy-based inter- and intra-specific interactions were assessed using water extracts from seedlings of the three varieties grown under HP and LP conditions. These extracts were tested on seeds of lettuce, the weed Dactyloctenium aegyptium, and the same rice variety. The shoot and root extracts from P-deficient seedlings reduced the germination of all recipient plants. Specifically, the shoot extract from P-deficient KDML105 seedlings reduced the germination index (GI) of lettuce seeds to 1%, while those from P-deficient RB and JHN seedlings produced GIs of 32% and 42%, respectively. However, when rice seeds were exposed to their own LP shoot and root extracts, their GIs increased up to 4-fold, compared with the HP extracts. Additionally, the shoot extracts from P-deficient plants also stimulated the germination of D. aegyptium by about 2–3-fold, whereas the root extracts did not have this effect. Therefore, P starvation led to the accumulation and exudation of phenolics in the shoots and roots of rice seedlings, altering their allelopathic activities. To adapt to P deficiency, rice seedlings potentially release signaling chemicals to suppress nearby competing species while simultaneously promoting their own germination and growth.

Ustilaginoidea virens is a common rice pathogen that can easily lead to a decline in rice quality and the production of toxins pose potential risks to human health. In this review, we present a comprehensive literature review of research since the discovery of rice false smut. We provide a comprehensive and, at times, critical overview of the main results and findings from related research, and propose future research directions. Firstly, we delve into the interaction between U. virens and rice, including the regulation of transcription factors, the process of U. virens infecting rice panicles, and the plant immune response caused by rice infection. Following that, we discuss the identification and characterization of mycotoxins produced by the pathogenic fungus, as well as strategies for disease management. We emphasize the importance of comprehensive agricultural prevention and control methods for the sustainable management of U. virens. This knowledge will update our understanding of the interaction between U. virens and rice plants, offering a valuable perspective for those interested in U. virens.

How to balance rice resistance and yield is an important issue in rice breeding. Plants with mutated necrotic lesion genes often have persistent broad-spectrum resistance, but this broad-spectrum resistance usually comes at the expense of yield. Currently, many necrotic lesion mutants in rice have been identified, and these genes are involved in disease resistance pathways. This review provides a detailed introduction to the characteristics, classification, and molecular mechanisms of necrotic lesion formation. Additionally, we review the molecular regulatory pathways of genes involved in rice disease resistance. Concurrently, we summarize the relationship between resistance and yield in rice using newly developed gene editing methods. We discuss a rational and precise breeding strategy to better utilize molecular design technology for breeding disease-resistant and high-yield rice varieties.

Applying iodine fertilizers to cultivate iodine-rich crops for daily intake is an effective approach for iodine supplementation, especially for aromatic rice. Field experiments were conducted during the early growing seasons of 2021 and 2022 to evaluate the impacts of foliar application of iodine fertilizer on aromatic rice and to explore the optimal iodine fertilizer concentration. At the full heading stage, six different concentrations of sodium iodide solutions of 0% (CK), 0.010% (T1), 0.025% (T2), 0.050% (T3), 0.075% (T4), and 0.100% (T5) were applied to indica aromatic rice cultivars Meixiangzhan 2 and Xiangyaxiangzhan. The results showed that sodium iodide treatments significantly increased the iodine and sodium contents in both leaves and grains. Compared with the CK, the T1 and T2 treatments increased the 2-acetyl-1-pyrroline (2-AP) content in mature grains by 8.41%‒101.66% and 13.58%‒ 74.60%, respectively. Improvements in the contents of 1-pyrroline-5-carboxylic acid, proline, 1-pyrroline, and methylglyoxal, as well as the activity of proline dehydrogenase were also detected. Additionally, sodium iodide treatments remarkably decreased the chalky grain rate, chalkiness area, and chalkiness degree of aromatic rice, with the T2 treatment exhibiting a 17.79%‒47.42% decrease in chalkiness degree compared with the CK. Meanwhile, T1 and T2 treatments showed beneficial impacts on chlorophyll content, photosynthetic characteristics, and yield components, while T3, T4, and T5 treatments exhibited adverse effects on leaf and grain yields. The linear discriminant analysis revealed significant differences between treatments. The correlation analysis and piecewise structural equation modeling showed that the iodine and sodium influenced the photosynthetic characteristics and chlorophyll content of the leaves, thereby regulating the 2-AP biosynthesis and yield components, ultimately affecting the 2-AP content and yield. Overall, this study suggests that foliar application of 0.025% sodium iodide is an effective method to enrich the iodine content in rice grains, improve the grain aroma and appearance quality of aromatic rice, without detrimental effects on grain yield.

Accurate genomic information is essential for advancing genetic breeding research in specific rice varieties. This study presented a gapless genome assembly of the indica rice cultivar Zhonghui 8015 (ZH8015) using PacBio HiFi, Hi-C, and ONT (Oxford Nanopore Technologies) ultra-long sequencing technologies, annotating 43 037 gene structures. Subsequently, utilizing this genome along with transcriptomic and metabolomic techniques, we explored ZH8015’s response to brown planthopper (BPH) infestation. Continuous transcriptomic sampling indicated significant changes in gene expression levels around 48 h after BPH feeding. Enrichment analysis revealed particularly significant alterations in genes related to reactive oxygen species scavenging and cell wall formation. Metabolomic results demonstrated marked increases in levels of several monosaccharides, which are components of the cell wall and dramatic changes in flavonoid contents. Omics association analysis identified differentially expressed genes associated with key metabolites, shedding light on ZH8015’s response to BPH infestation. In summary, this study constructed a reliable genome sequence resource for ZH8015, and the preliminary multi-omics results will guide future insect-resistant breeding research.